Problem: Khan.scratchpad.disable(); For every level Luis completes in his favorite game, he earns $490$ points. Luis already has $230$ points in the game and wants to end up with at least $3220$ points before he goes to bed. What is the minimum number of complete levels that Luis needs to complete to reach his goal?
Answer: To solve this, let's set up an expression to show how many points Luis will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Luis wants to have at least $3220$ points before going to bed, we can set up an inequality. Number of points $\geq 3220$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3220$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 490 + 230 \geq 3220$ $ x \cdot 490 \geq 3220 - 230 $ $ x \cdot 490 \geq 2990 $ $x \geq \dfrac{2990}{490} \approx 6.10$ Since Luis won't get points unless he completes the entire level, we round $6.10$ up to $7$ Luis must complete at least 7 levels.